1. Field of the Invention
The invention relates to the production of methane from carbon monoxide. More particularly, it relates to a methanation process capable of effectively utilizing the CO content of waste effluent streams employed as feed gas.
2. Description of the Prior Art
The production of low-cost methane as a replacement for natural gas has been the subject of considerable interest in light of the energy requirements of industrial societies throughout the world. The COthane process has been developed in response to such interest and concerns. It is particularly advantageous in that this process is capable of utilizing dilute carbon monoxide-containing gas streams without the necessity for the preliminary concentration that has precluded the use of such streams in conventional techniques for the production of methane from carbon monoxide and hydrogen. Thus, waste streams, such as the effluent from blast furnace operations, carbon black off-gas, underground coal gasification and the like, can be effectively utilized for the production of methane although such streams previously were unsuitable as useful sources of CO.
The COthane process is a cyclic, essentially two-step process in which a surface layer of active surface carbon is deposited on a catalyst and is then contacted with steam or hydrogen to convert the active surface carbon to methane and carbon dioxide. This essentially two-step process is repeated in cyclic operations without the need for regenerating the catalyst as a necessary additional step of the cyclic operation. Upon separation from carbon dioxide by conventional means, the methane is recovered in the form of a low-cost, relatively pure product, with the process effectively utilizing the carbon monoxide values of dilute carbon monoxide containing waste gas streams or other such sources of CO-containing feed gas for the process.
There is, of course, a desire in the art to continually improve the available methanation technology. With respect to the COthane process in particular, it is desirable to develop processing improvements and modifications to enhance the overall process, especially to broaden the scope of waste gas streams capable of being used as feed gas streams while maintaining or enhancing the effective CO utilization of the process as applied to such streams.
It is an object of the invention, therefore, to provide an enhanced process for the production of methane from carbon monoxide-containing gas streams.
It is another object of the invention to provide an improved process for the effective utilization of CO-containing waste gases for the production of methane.
It is a further object of the invention to provide a process for the production of methane from an enlarged scope of waste streams as suitable sources of CO for the indicated cyclic, essentially two-step methanation process.